Table 1.

Major factors involved in cancer stem cell-related drug resistance

Associated factor	Major normal biological function	Functions in cancer drug resistance	Major Ref.	Additional remarks
ABC transporters	Efflux toxic metabolites	Efflux anticancer drugs, reducing ROS	[30,31,33,35,38,56,62,64] [61]	Functional marker of CSC
Low oxidative stress	Anti-apoptosis, detoxification	Maintaining stemness, preventing therapy-induced apoptosis	[48,50,51] [19,49,50,53,56,58]
ALDH	Oxidation of aldehydes, detoxification	Detoxification, reducing ROS, inducing CSC	[13,41,42] [42,44] [45]	Hallmark of CSC
Metabolic reprogramming	Not applicable	Reducing ROS, adaptation to TME	[73,75] [13,27,69,84,85]	Hallmark for cancer metabolism
Autophagy	Removal and recycling cellular components	Inducing CSC, promoting survival	[48,100] [30,100,103,105-109]	Mitophagy reduces ROS and promotes survival